The present invention relates to torque transfer drive assemblies, in general, and more particularly to a concentric pulley drive assembly having first and second pulleys concentrically mounted about a drive motor axle for transmitting torque from the first pulley to the second pulley utilizing a torque transfer medium to induce annular rotation of the second pulley about the motor axle commensurate with the annular rotation of the first pulley and to pivotally position a support structure coupled to the second pulley about the motor axle in conjunction with the annular rotation of the second pulley.
In general, airborne antenna and sensor gimbal systems utilize pulley drive mechanisms with medium to light torque requirements. These systems generally contain two or more pulleys whose axles are separated one from the other with the span therebetween bridged by a torque transmitting tape or belt. Generally, a platform structure for supporting a radar antenna or sensor is coupled to one of the pulleys for pivotal positioning about the axle thereof. In these systems, the structural envelope occupied by the pulley drive assembly as the platform moves between its limit positions is almost always larger than the envelope occupied by a comparably performing concentric pulley drive system. As a result, the physical space swept in the motion of the structural envelope of the multiple axle assembly becomes a limitation to the gimbal travel.
The present invention as described in connection with a preferred embodiment herebelow offers a more compact pulley drive mechanism. The preferred embodiment utilizes a set of pulleys interconnected concentrically one to the other with a zero backlash torque transfer tape medium. As a result of this unique concentric pulley assembly, the structural envelope occupied by the drive assembly as the platform moves between its limit positions is reduced substantially allowing greater angular travel without mechanical interference.